These mobs come in packs of 8 or 9 and should be burned down by AoE. Have a tank either bind all the guests to him by using his AoE taunt or have all decently armored damage dealers in your raid each pick one or two of them from the pull to spread out the damage and build up some minor aggro on them before initiating the AoE fire a few seconds later. Starting the AoE too early causes all guests to gang up on one player which often results in certain death for the poor lad.

Despite being all named the same, the Phantom Guests have different and random abilities which are not discernible prior to the pull. Since some of them can be healers, capable of completely restoring the health of one of their fellow guests, nuking them down one by one with focus damage can be a tedious and risky undertaking.

The Phantom Ghosts sitting on the largest table in the banquet hall in front of Moroes are two separate groups that can be pulled individually from each side of the table.